Anyone upgraded a stock e30 m3 fuel pump on a 24v swap?

[m3j0n]

Looking to do this. My pump doesn't seem to be able to handle the 6 24lb injectors at WOT high RPM..

[mpowerful]

I have a stock e36 pump in mine with 24lb injectors and its plenty

[Alpina]

I had stock E30 325 on my S38B38,,, and it was also more than enough

[m3j0n]

I have a stock e36 pump in mine with 24lb injectors and its plenty

I guess Mine is just getting weak... It only does it occasionally. I hooked up a gauge and drove it around. Definitely lost a bit of pressure higher in RPM and heavy throttle. I think the FPR is ok, and really think its a weak HPFP in the tank.

did you keep the stock LPFP located under the car when you upgraded to the e36 pump? or does that get bypassed? My car was sitting for at least 4 years before I did the swap.

[nrubenstein]

You have the pumps backwards. In tank is low pressure, below the car is high.

If you "upgrade" the pump, bypass the under car pump and install a high pressure pump in the tank.

Stock pumps should be more than plenty for an S50US.

[mpowerful]

Mine was a late model setup to begin with. So it was not dual pump.

[m3j0n]

You have the pumps backwards. In tank is low pressure, below the car is high.

If you "upgrade" the pump, bypass the under car pump and install a high pressure pump in the tank.

Stock pumps should be more than plenty for an S50US.

Cool, thanks for the tip! That's what I was planning to do. I bought a walbro gss342 (flows 255LPH) to put in-tank. I figured this was the easiest/cheapest way to fix the issue. Is there anyway to diagnose which pump is the culprit (or the FPR for that matter)?

Mine was a late model setup to begin with. So it was not dual pump.

My car is a 1990, didn't think it got much later than that.

[328ijunkie]

Stock (working) pump(s) will flow ~36lb injectors fine.

[mpowerful]

Ive never seen a late model with dual pump setup unless someone added an inline pump in an attempt to cure a failing intank pump.

[328ijunkie]

A lot
Of
M3s had dual pumps

[mpowerful]

Ahh i completely missed the m3 part. Yeah understandable now. Im blonde what can i say.

[ForcedFirebird]

Stock (working) pump(s) will flow ~36lb injectors fine.

this.



The in tank late model Bosch pump is rated over 130l/hr which will support ~300-ish hp.

[m3j0n]

this.



The in tank late model Bosch pump is rated over 130l/hr which will support ~300-ish hp.

I must have a 600 hp car

According to my gauge, fuel pressure tapers off just a few pounds at WoT in the high RPM. 43-45psi occasionally tapering to 35-38psi. I ordered a new walbro that flows 255lph, but wanted to make sure a failing fuel pump is the only scenario that could be wrong in the fuel system. The car does have a new fuel filter.

[matthugie]

The screen on your in-tank pump could also be somewhat clogged. I would replace that when you replace your pump (if you do the in-tank one) while you're in there.

[m3j0n]

The screen on your in-tank pump could also be somewhat clogged. I would replace that when you replace your pump (if you do the in-tank one) while you're in there.

cool. that's a great point.. where can I buy that separately?